This article presents the results of the first study on the relationship between Internet addiction (IA) and Type D personality (D is for distressed) in Slovakia and is the first attempt to examine the impact of Type D personality in the prediction of IA beyond personality dimensions. Altogether 405 adult Slovak Internet users (aged from 18 to 45 years) filled out the following questionnaires: IRPS, DS14, and NEO-FFI. The results showed that there wasn’t a significant effect of the Type D personality on levels of IRPS after con- trolling for the effect of Big-Five personality traits. The Big Five personality dimensions and demographics explained 21.1 % of variance in IA. According to our results the typical adult addicted to the Internet could be characterized as a young introverted unconscientious and disagreeable neurotic. Future research should concentrate more on the creation and validation of the model of IA.